1. Field of the Invention
The present invention relates to a mobile communication system. More particularly, the present invention relates to a method and apparatus for consuming low power by a terminal in a mobile communication system.
2. Description of the Related Art
Mobile communication systems have been developed to provide voice services while ensuring the user's activity. However, the mobile communication systems have gradually expanded their respective services from voice services to include data services. At present, the mobile communication systems have evolved to provide high-speed data services. However, mobile communication systems according to the related art suffer from a lack of resources. More advanced wireless communication systems are required to meet the increasing users' demand for high-speed services.
To meet these needs, standardization for a Long Term Evolution (LTE) communication system, one of the next-generation wireless communication systems under development, is underway in 3rd Generation Partnership Project (3GPP). Because the LTE system basically supports only the packet services, the LTE standard has proposed a Circuit Switched FallBack (CSFB) service, in which in order to provide a voice call to a user, upon receiving an incoming voice call, a terminal camping on an LTE network drops its connection to the LTE network, and accesses the legacy 3rd Generation (3G) network (or Circuit Switched (CS) network) to provide a voice call service. In addition to CSFB, the LTE standard has proposed a Voice over LTE (VoLTE) service as technology for supporting a voice call service in the LTE network. According to the VoLTE service, a terminal converts the user's voice into packet data and transmits the packet data across the LTE network.
As the LTE system applies the voice call service that uses the legacy 3G CS network, to the Packet Switched (PS) data network, a protocol for voice call control between a terminal and the network is required. To this end, a Session Initiation Protocol (SIP) protocol is used. The SIP protocol provides multiple functions, such as a message delivery function of sending a call to the other party when a user makes a call, a function of receiving and responding to a call message upon receiving the call message from the other party, a function of accepting, rejecting or dropping the call depending on the user's input, and a function of determining whether the terminal is normally connected to the network.
FIG. 1 illustrates a structure of a terminal according to the related art.
Referring to FIG. 1, the terminal includes an Application Processor (AP) 100, a Session Inter-Process Communication (SIPC) 120, and a Communication Processor (CP) 130. The Session Inter-Process Communication (SIPC) 120 operates for interworking between the AP 100 and the CP 130.
In the terminal, the SIP protocol is implemented in the AP 100.
It is assumed that an SIP message and/or a voice packet are received at the terminal from a network.
Upon receiving a voice packet from the network, a Packet Data Convergence Protocol (PDCP) filter 134 in the CP 130 of the terminal transfers the voice packet to a voice engine 132 via a Transfer Control Protocol/Internet Protocol (TCP/IP) 136 in the CP 130, and the voice engine 132 processes the voice packet, allowing the user to hear the voice.
Upon receiving an SIP message from the network, the PDCP filter 134 in the CP 130 sends the SIP message to an SIP stack 115 in the AP 100, so that an appropriate operation is performed for each message. For example, upon receiving the SIP message from the network, the PDCP filter 134 in the CP 130 may send the SIP message to the SIP stack 115 in the AP 100 by way of the TCP/IP 105 in the AP 100. The AP 100 may include an IMS library 110 comprising the SIP stack 115.
FIG. 2 is a flowchart illustrating an operation of a terminal according to the related art.
Referring to FIG. 2, in step 201, the PDCP filter 134 of the CP 130 included in the terminal receives an SIP message in a situation in which there is no user input. In step 203, the PDCP filter 134 sends the received SIP message to the SIP stack 115 in the AP 100, which is responsible for processing an SIP protocol, even in the situation in which there is no user input. In step 205, the SIP stack 115 in the AP 100 handles the received SIP message.
Because the terminal attempts to ensure the maximum performance and run time within the terminal limitations (e.g., limited size, processing power, and the like), reduction of the power consumption of the terminal is very important. However, because the SIP stack 115 used to control VoLTE voice calls exists in the AP 100, the AP 100 is responsible for generating an SIP message and handling a received SIP message. When the user takes an action of making (sending) or receiving a voice call, the AP 100 is enabled in order to activate a User Interface (UI) of the terminal. Therefore, the terminal does not need to additionally enable the AP 100 when the terminal needs to handle an SIP message.
However, when there is a need to handle an SIP message in a situation in which there is no user input, the terminal should enable the AP 100 in order to handle the SIP message, thereby causing the terminal to consume relatively more power.
Therefore, a need exists for a method and apparatus for consuming low power by a terminal, in which when there is a need to process an Session Initiation Protocol (SIP) protocol in a situation in which there is no user input.
The above information is presented as background information only to assist with an understanding of the present disclosure. No determination has been made, and no assertion is made, as to whether any of the above might be applicable as prior art with regard to the present invention.